BEGIN:VCALENDAR VERSION:2.0 PRODID:-//jEvents 2.0 for Joomla//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VTIMEZONE TZID:America/New_York BEGIN:STANDARD DTSTART:20211107T010000 RDATE:20220313T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20221106T010000 RDATE:20230312T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20231105T010000 RDATE:20240310T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20241103T010000 RDATE:20250309T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20251102T010000 RDATE:20260308T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20261101T010000 RDATE:20270314T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20271107T010000 RDATE:20280312T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:STANDARD DTSTART:20281105T010000 RDATE:20290311T030000 TZOFFSETFROM:-0400 TZOFFSETTO:-0500 TZNAME:America/New_York EST END:STANDARD BEGIN:DAYLIGHT DTSTART:20210330T170000 RDATE:20211107T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20220313T030000 RDATE:20221106T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20230312T030000 RDATE:20231105T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20240310T030000 RDATE:20241103T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20250309T030000 RDATE:20251102T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20260308T030000 RDATE:20261101T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20270314T030000 RDATE:20271107T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT BEGIN:DAYLIGHT DTSTART:20280312T030000 RDATE:20281105T010000 TZOFFSETFROM:-0500 TZOFFSETTO:-0400 TZNAME:America/New_York EDT END:DAYLIGHT END:VTIMEZONE BEGIN:VEVENT UID:021d65782a70925f16a11581a6dda4e5 CATEGORIES:Experimental Mathematics Seminar CREATED:20220222T120314 SUMMARY:Sharing Pizza in n Dimensions LOCATION:Zoom DESCRIPTION:Title: Sharing Pizza in n Dimensions Speaker: Richard Ehrenborg, University of Kentucky Date: Thursday, March 31st, 2022 Time: 5:00pm–5:48pm Place: zo om Short abstract: We introduce and prove the n-dimensional Pizza Theorem. This is joint work with Sophie Morel and Margaret Readdy. Long abstract: We introduce and prove the n-dimensional Pizza Theorem. Let H be a real ndime nsional hyperplane arrangement. If K is a convex set of finite volume, the pizza quantity of K is the alternating sum of the volumes of the regions ob tained by intersecting K with the arrangement H. We prove that if H is a Co xeter arrangement different from An 1 such that the group of isometries W g enerated by the reflections in the hyperplanes of H contains the negative o f the identity map, and if K is a translate of a convex set that is stable under W and contains the origin, then the pizza quantity of K is equal to z ero. Our main tool is an induction formula for the pizza quantity involving a subarrangement of the restricted arrangement on hyperplanes of H that we call the even restricted arrangement. We get stronger results in the case of balls. We prove that the pizza quantity of a ball containing the origin vanishes for a Coxeter arrangement H with |H| ? n an even positive integer. This is joint work with Sophie Morel and Margaret Readdy.\n X-ALT-DESC;FMTTYPE=text/html:

Title: Sharing Pizza in n Dimensions Speaker: Richard Ehrenborg, Univers ity of Kentucky Date: Thursday, March 31st, 2022 Time: 5:00pm–5:48pm Place: zoom Short abstract: We introduce and prove the n-dimensional Pizza Theore m. This is joint work with Sophie Morel and Margaret Readdy. Long abstract: We introduce and prove the n-dimensional Pizza Theorem. Let H be a real n dimensional hyperplane arrangement. If K is a convex set of finite volume, the pizza quantity of K is the alternating sum of the volumes of the region s obtained by intersecting K with the arrangement H. We prove that if H is a Coxeter arrangement different from An 1 such that the group of isometries W generated by the reflections in the hyperplanes of H contains the negati ve of the identity map, and if K is a translate of a convex set that is sta ble under W and contains the origin, then the pizza quantity of K is equal to zero. Our main tool is an induction formula for the pizza quantity invol ving a subarrangement of the restricted arrangement on hyperplanes of H tha t we call the even restricted arrangement. We get stronger results in the c ase of balls. We prove that the pizza quantity of a ball containing the ori gin vanishes for a Coxeter arrangement H with |H| ? n an even positive inte ger. This is joint work with Sophie Morel and Margaret Readdy.

CONTACT:Richard Ehrenborg, University of Kentucky X-EXTRAINFO:Zoom link: https://rutgers.zoom.us/j/94346444480\nPassword password: The 20 th Catalan number, alias (40)!/(20!*21!), alias 6564120420 DTSTAMP:20260829T173953 DTSTART;TZID=America/New_York:20220331T170000 DTEND;TZID=America/New_York:20220331T180000 SEQUENCE:0 TRANSP:OPAQUE END:VEVENT END:VCALENDAR